| 1. |
- Nonomura, Arthur M., et al.
(författare)
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The carbon reactions of photosynthesis : role of lectins and glycoregulation
- 2020
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Ingår i: Photosynthetica (Praha). - Prague : Institute of Experimental Botany of the Academy of Sciences of the Czech Republic. - 0300-3604 .- 1573-9058. ; 58:5, s. 1090-1097
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Forskningsöversikt (refereegranskat)abstract
- Modulation of glycoregulation in agriculture is reviewed here with emphasis on the elucidation of previously unknown pathways involving vacuolar lectins as well as a bypass of lectins that direct free sugars toward productivity. The reversible binding sequences of the endogenous lectin cycle are compared to an induced lectin bypass, as follows. (1) In the cycle, carbohydrate ligands, with similar binding specificities that compete for binding sites on lectins, are involved in the natural cycle of sugar exchanges. (2) For the bypass, tightly bound ligands that occupy lectins prevent free sugars from binding, making them available for productivity. This bypass is induced by methyl-α-D-mannopyranoside, a biochemical plant growth regulator for photosynthesis. Integration of this novel technology, with structural elements crucial for ligand binding by the lectins and with nitrogen assimilation, provides the basis for successful modulation of glycoregulation in crops for enhancement of quality and quantity.
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| 2. |
- Voitsekhovskaja, O. V., et al.
(författare)
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Photosynthetic activity as assessed via chlorophyll a fluorescence suggests a role of potassium channels in root to shoot signaling
- 2020
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Ingår i: Photosynthetica (Praha). - : Institute of Experimental Botany. - 0300-3604 .- 1573-9058. ; 58:2, s. 608-621
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Tidskriftsartikel (refereegranskat)abstract
- Potassium is indispensable for plant growth. Recently, a role of K+ channels has emerged in sensing and transducing stress and nutrient status. Tetraethylammonium (TEA(+)) is a specific blocker of K+ transport and affects K+ channel gene expression. Two barley varieties with contrasting salinity tolerance, and a chlorophyll b-less mutant, were grown either in the presence of TEA(+) alone or combined with NaCl, at two different concentrations of external K+ and Ca2+, and were analyzed nine days after germination. Chlorophyll a transients monitored via JIP-tests were used to evaluate the state of the photosynthetic machinery. In contrast to reported responses to K+ deficiency, TEA(+) inhibited shoot growth while inducing root growth and increasing photosynthetic performance. Both TEA(+) and NaCl induced the appearance of negative K-bands in OJIP kinetics and an increase in PIABS, indicating a stimulation of photosynthesis by increased sink strength in the context of root to shoot signaling.
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| 3. |
- Lazár, Dušan, et al.
(författare)
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Light quality, oxygenic photosynthesis and more.
- 2022
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Ingår i: Photosynthetica. - 0300-3604. ; 60:SI, s. 23-56
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Forskningsöversikt (refereegranskat)abstract
- Oxygenic photosynthesis takes place in thylakoid membranes (TM) of cyanobacteria, algae, and higher plants. Itbegins with light absorption by pigments in large (modular) assemblies of pigment-binding proteins, which thentransfer excitation energy to the photosynthetic reaction centers of photosystem (PS) I and PSII. In green algaeand plants, these light-harvesting protein complexes contain chlorophylls (Chls) and carotenoids (Cars). However,cyanobacteria, red algae, and glaucophytes contain, in addition, phycobiliproteins in phycobilisomes that are attachedto the stromal surface of TM, and transfer excitation energy to the reaction centers via the Chl a molecules in the innerantenna of PSI and PSII. The color and the intensity of the light to which these photosynthetic organisms are exposedin their environment have a great influence on the composition and the structure of the light-harvesting complexes(the antenna) as well as the rest of the photosynthetic apparatus, thus affecting the photosynthetic process and even theentire organism. We present here a perspective on ‘Light Quality and Oxygenic Photosynthesis’, in memory of GeorgeChristos Papageorgiou (9 May 1933–21 November 2020; see notes a and b). Our review includes (1) the influence ofthe solar spectrum on the antenna composition, and the special significance of Chl a; (2) the effects of light quality onphotosynthesis, measured using Chl a fluorescence; and (3) the importance of light quality, intensity, and its durationfor the optimal growth of photosynthetic organisms.
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